Pneumatic boom support for hand tools

ABSTRACT

A boom is connected to a support member through a hinge connection which permits both vertical and horizontal movement of the end of the boom. A pneumatic linear actuator, including a cylinder and a piston, is connected between the boom and the support member at the hinge such that the length of the actuator changes with vertical movement of the boom about the hinge support. A bleed-type adjustable pneumatic pressure regulator controls the air pressure applied to the actuator so as to exactly counterbalance the weight of the boom and tools supported on the end of the boom.

United States Patent [1 1 Johnson Nov. 4, 1975 PNEUMATIC BOOM SUPPORTFOR HAND TOOLS 22 Filed: Dec. 14, 1973 [21] Appl. No; 424,907

52 us. Cl. 248/13; 248/123; 248/280 51 Int. cl. B66D 1/00; A47F 5/00 58Field of Search 248/123, 280, 292, 325, 248/13 [56] 0 References CitedUNITED STATES PATENTS I 1,446,648 2/1923 Kostlan 248/123 X 1,819,8428/1931 Moore l 248/292 X 2,125,586 8/1938 POhl 248/123 0 2,156,8625/1939 Maugard 248/123 2,502,510 4/1950 Daugert 248/123 2,700,524 1/1955Lauterbach 248/280 4 3,134,340 5/1964 Olsen et al 248/325 X 3,259,3517/1966 Olsen 248/325 3,259,352 7/1966 Olsen 248/325 3,721,416 3/1973Goudreau 248/325 3,747,886 7/1973 Carlson 248/325 Primary Examiner-J.Franklin Foss [57] ABSTRACT A boom is connected to a support memberthrough a hinge connection which permits both vertical and horizontalmovement of the end of the boom. A pneumatic linear actuator, includinga cylinder and a piston, is connected between the boom and the supportmember at the hinge such that the length of the actuator changes withvertical movement of the boom about the hinge support. A bleed-typeadjustable pneumatic pressure regulator controls the air pressureapplied to the actuator so as to exactly counterbalance the weight ofthe boom and tools supported on the end of the boom.

5 Claims, 2 Drawing figures US. Patent Nov. 4, 1975 3,917,200

PNEUMATIC BOOM SUPPORT FOR HAND TOOLS FIELD OF THE INVENTION Thisinvention relates to a tool support, and more particularly, is relatedto a pneumatically-operated support for manually manipulated tools.

BACKGROUND OF THE INVENTION In using manually-manipulated tools, such aspower tools, spray guns, and the like, it is desirable to counterbalancein some manner the weight of the tool without restricting the manualmanipulation of the tool by the user. For example, it has heretoforebeen proposed to suspend the tool on a spring such that a portion of theweight of the tool was absorbed by the deflection of the spring.However, because the force produced by the spring varies as a functionof deflection of the spring, movements of the tool by the operatorrequire a varying force supplied by the operator to change thedeflection of the spring in moving the tool about from position toposition. Particularly in the use of a spray gun which must be scannedover a large area, the conventional spring counterbalancing arrangementhas 'not proved satisfactory.

SUMMARY OF THE INVENTION The present invention is directed to a loadcounterbalancing support mechanism for a spray gun or otherhand-manipulated tool which permits a wide range of movement in both avertical and horizontal direction with the load of the tool beingcompletely counterbalanced in any position. In brief, this isaccomplished by providing a boom which is connected to a support memberby hinge means which permits both horizontal and vertical movement ofthe boom. The tool or other load is suspended from the end of the boom.A pneumatic linear actuator, including a cylinder and piston, isconnected between the boom and the support member adjacent to the hingesuch that the length of the actuator changes with vertical movement .ofthe boom about the hinge connection. The linear actuator is energizedfrom a source of compressed air through a bleeder type regulator whichmaintains the pressure in the actuator substantially constant regardlessof changes in the volume of the actuator as the length of the actuatorchanges with vertical movements of the boom.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding ofthe invention, reference should be made to the accompanying drawing,wherein:

FIG. 1 is an elevational view of the counterbalanced load supportingstructure of the present invention; and

FIG. 2 is a detailed view, partly in section, showing the hinge andpneumatic actuator assembly.

DETAILED DESCRIPTION Referring to the drawing in detail, the numeralindicates generally a portable base preferably provided with wheels 12for moving the base about. However, it will be understood that the basemay be permanently attached to the floor or other structure in thevicinity of the work area.

Attached to the top of the base 10 is a support member 14 preferably inthe form of a hollow pipe having a 90 bend so that the lower end 16extends vertically up from the base 10 while the outer end 18 extendshorizontally away from the base 10. The lower end 16 is welded orotherwise secured to the base 10 and is further anchored by reinforcingflanges 20. A ballast weight 22 may be provided on the base 10 toprovide added stability.

Attached to the outer end 18 of the support member 14 is a boom 24. Theboom 24 is attached to the support member 14 through a double hingeassembly indicated generally at 26 and described in more detail below inconnection with FIG. 2. A portable power tool, spray gun, or otherdevice, indicated generally at 27, is suspended from the end of the boom24 by a flexible line or cable 28.

To counterbalance the weight of the boom 24 and the tool 27, a pneumaticlinear actuator 30 is provided which interconnects the boom 24 andsupport member 14 in the manner shown in more detail in FIG. 2. Thepneumatic linear actuator is pressurized from a source of compressedair, such as indicated generally at 32, through a pressure regulator 34mounted on the support member 14. Air under relatively high pressure isapplied to the input of the pressure regulator 34 through an air line36. The output of the pressure regulator 34 in turn is connected to thelinear actuator through an air line 38.

The air regulator 34 is of a type referred to as a bleeder or relievingtype regulator, that is, an adjustable regulator in which the outputpressure is maintained substantially constant at any selected levelbelow the pressure at the input to the regulator. Any drop in thepressure at the output due to the demands of the load results in anincrease of air supplied from the input to bring the pressure back up tothe regulated level, whereas any increase in pressure at the outputabove the regulated level causes a bleeding of air from the output sideof the regulator to bring the pressure back down to the regulated level.Such regulators are well known in the pneumatic regulator art andreadily available from a number of manufacturers. Further description ofthe regulator is therefore not believed necessary to an understanding orpractice of the present invention.

Referringto FIG. 2, the hinge structure 26 includes a tubular member 40which is welded or otherwise rigidly secured to the outer end 18 of thesupport member 14 with the axis of the tubular member 40 extendingvertically. Bearing bushings 42 and 44 are inserted in the two ends ofthe tubular member 40. A hinge shaft 46 is journaled in the bushings 42and 44. The upper end of the shaft 46 has a flange 48 which engages thetop surface of the bushing 42.

The boom 24 is connected to the shaft 46 through a conventional hingeincluding a pair of hinge plates 50 and 52 pivotally joined by a hingepin 54. The hinge plate 50 is rigidly attached to the top of the flange48 while the hinge plate 52 is rigidly attached to the end of the boom24, thus permitting the boom' 24 to move vertically about the axis ofthe hinge pin 54 relative to the support member 18. At the same time,the boom 24 can rotate horizontally about the axis of the shaft 46 byrotation of the shaft within the bushings 42 and 44.

The linear actuator 30 is a conventional pneumatic actuator including acylinder 56, piston 58, and piston rod 60. The upper end of the cylinder56 is hingedly connected to the boom 24 through a clevis member 62 whichextends on either side of a pipe 64 connected to and projecting downfrom the underside of the boom 24. A pin 66 connects the clevis member62 to the pipe 64.

The lower end of the piston rod 60 in turn is hingedly secured to thelower end of the shaft 46 by a bracket 68 which is bolted or otherwisesecured to the lower end of the shaft 46. The lower end of the pistonrod 60 is connected to the bracket 68 through a suitable pin 70.

From the above description it will be seen that vertical movement of theend of the boom 24 varies the length of the linear actuator 30. Adownward movement of the boom 24 decreases the volume within the linearactuator, causing an increase in the back pres sure on the regulator 34.By bleeding off the air, the regulator maintains the pressuresubstantially constant with shortening of the linear actuator by thedownward movement of the boom. Similarly, an upward movement of the boomincreases the length of the actuator, producing an increase in volumeand decrease in pressure within the actuator cylinder. The decrease inpressure is compensated by the regulator 34 to maintain the pressuresubstantially constant. Thus the counterbalancing force produced by thelinear actuator is substantially constant regardless of the verticalposition of the boom. The user of the tool 27 can move the toolvertically to any position within the normal limits of the supportingstructure and the weight of the tool is completely counterbalanced bythe action of the linear actuator 30 and pressure regulator 34. At thesame time, the tool 27 is freely movable horizontally by virtue of therotation of the shaft 46 within the bushings 42 and 44.

What is claimed is:

l. A movable support for a hand-manipulated tool, such as a spray gun,permitting a wide range of movement in both vertical and horizontaldirection, comprisa support member including a substantiallyhorizontally extending first boom, a second boom forming an extension ofsaid first boom, hinge means connecting one end of the second boom tothe free end of said first boom, the hinge means providing movement ofthe second boom relatively to the first boom about a vertical as well ashorizontal axis, means connecting the load to the other end of thesecond boom, a pneumatic linear actuator including a cylinder andpiston, means, including at least a part of the hinge means, connectingone end of the actuator to the second boom and the other end of theactuator to the first boom such that the length of the actuator changeswith vertical movement of the second boom about the horizontal axis ofthe hinge means, and means including a pneu- A ment in both a verticaland horizontal direction, com-,

prising: a support member in the form of a first boom, a second boomforming an extension of said first boom,

hinge means connecting the second boom to the sup-' port member, thehinge means providing vertical as well as horizontal movement of thesecond boom about the hinge means and including a first hinge unitsecured to the support member and a second hinge unit secured to thesecond boom, the two hinge units being connected to each other andhaving mutually perpendicular hinge axes, means connecting the load toone end of the second boom, a pneumatic linear actuator including acylinder and piston and pivotally secured at one end to the second boomadjacent the end secured to the second hinge unit, the other endv of thelinear actuator being pivotally connected to the common connectionbetween the first and second hinge units, means connecting one end ofthe actuator to the second boom and the other end to the support membersuch that the length of the actuator changes with vertical movement ofthe second boom about the hinge means, and means including a pneumaticpressureregulator connecting the cylinder to a pressurizedpneumaticsource, the regulator pressurizing the actuator sufficiently tocounterbalance the weight of the second boom and load.

1. A movable support for a hand-manipulated tool, such as a spray gun,permitting a wide range of movement in both vertical and horizontaldirection, comprising: a support member including a substantiallyhorizontally extending first boom, a second boom forming an extension ofsaid first boom, hinge means connecting one end of the second boom tothe free end of said first boom, the hinge means providing movement ofthe second boom relatively to the first boom about a vertical as well ashorizontal axis, means connecting the load to the other end of thesecond boom, a pneumatic linear actuator including a cylinder andpiston, means, including at least a part of the hinge means, connectingone end of the actuator to the second boom and the other end of theactuator to the first boom such that the length of the actuator changeswith vertical movement of the second boom about the horizontal axis ofthe hinge means, and means including a pneumatic pressure regulatorconnecting the cylinder to a pressurized pneumatic source, the regulatorpressurizing the actuator sufficiently to counterbalance the weight ofthe second boom and load.
 2. Apparatus of claim 1 wherein the pressureregulator is adjustable.
 3. Apparatus of claim 1 wherein the regulatormaintains substantially constant pressure in the cylinder with changesin volume as the actuator changes length.
 4. Apparatus of claim 3wherein the regulator is a bleeding type regulator.
 5. A movable supportfor a hand-manipulated tool, such as a spray gun, permitting a widerange of movement in both a vertical and horizontal direction,comprising: a support member in the form of a first boom, a second boomforming an extension of said first boom, hinge means connecting thesecond boom to the support member, the hinge means providing vertical aswell as horizontal movement of the second boom about the hinge means andincluding a first hinge unit secured to the support member and a secondhinge unit secured to the second boom, the two hinge units beingconnected to each other and having mutually perpendicular hinge axes,means connecting the load to one end of the second boom, a pneumaticlinear actuator including a cylinder and piston and pivotally secured atone end to the second boom adjacent the end secured to the second hingeunit, the other end of the linear actuator being pivotally connected tothe common connection between the first and second hinge units, meansconnecting one end of the actuator to the second boom and the other endto the support member such that the length of the actuator changes withvertIcal movement of the second boom about the hinge means, and meansincluding a pneumatic pressure regulator connecting the cylinder to apressurized pneumatic source, the regulator pressurizing the actuatorsufficiently to counterbalance the weight of the second boom and load.